From 37eccedd84d6c047f1af3011342f816228fe9070 Mon Sep 17 00:00:00 2001
From: Ilya Etingof <etingof@gmail.com>
Date: Mon, 4 Sep 2017 14:04:54 +0200
Subject: [PATCH] Added `by_path` root device hint

With the introduction of the `by_path` introspection
attribute at the IPA [1], it is now possible to leverage
the stable block device names for root device hinting.

This patch adds the `by_path` attribute to the collection
of valid root device hints.

1. https://review.openstack.org/#/c/498489/

Change-Id: I6f1c6b5ec5face7180aeb2d1aeebe50a6eb33f24
---
 ironic_lib/tests/test_utils.py | 12 +++++++++---
 ironic_lib/utils.py            |  4 +++-
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/ironic_lib/tests/test_utils.py b/ironic_lib/tests/test_utils.py
index 7e407f35..16af919b 100644
--- a/ironic_lib/tests/test_utils.py
+++ b/ironic_lib/tests/test_utils.py
@@ -198,7 +198,7 @@ class ParseRootDeviceTestCase(base.IronicLibTestCase):
             'serial': 'foo-serial', 'vendor': 'foo VENDOR with space',
             'name': '/dev/sda', 'wwn_with_extension': '123456111',
             'wwn_vendor_extension': '111', 'rotational': True,
-            'hctl': '1:0:0:0'}
+            'hctl': '1:0:0:0', 'by_path': '/dev/disk/by-path/1:0:0:0'}
         result = utils.parse_root_device_hints(root_device)
         expected = {
             'wwn': 's== 123456', 'model': 's== foo%20model',
@@ -206,7 +206,8 @@ class ParseRootDeviceTestCase(base.IronicLibTestCase):
             'vendor': 's== foo%20vendor%20with%20space',
             'name': 's== /dev/sda', 'wwn_with_extension': 's== 123456111',
             'wwn_vendor_extension': 's== 111', 'rotational': True,
-            'hctl': 's== 1%3A0%3A0%3A0'}
+            'hctl': 's== 1%3A0%3A0%3A0',
+            'by_path': 's== /dev/disk/by-path/1%3A0%3A0%3A0'}
         self.assertEqual(expected, result)
 
     def test_parse_root_device_hints_with_operators(self):
@@ -216,13 +217,14 @@ class ParseRootDeviceTestCase(base.IronicLibTestCase):
             'name': '<or> /dev/sda <or> /dev/sdb',
             'wwn_with_extension': 's!= 123456111',
             'wwn_vendor_extension': 's== 111', 'rotational': True,
-            'hctl': 's== 1:0:0:0'}
+            'hctl': 's== 1:0:0:0', 'by_path': 's== /dev/disk/by-path/1:0:0:0'}
 
         # Validate strings being normalized
         expected = copy.deepcopy(root_device)
         expected['model'] = 's== foo%20model'
         expected['vendor'] = 's== foo%20vendor%20with%20space'
         expected['hctl'] = 's== 1%3A0%3A0%3A0'
+        expected['by_path'] = 's== /dev/disk/by-path/1%3A0%3A0%3A0'
 
         result = utils.parse_root_device_hints(root_device)
         # The hints already contain the operators, make sure we keep it
@@ -307,6 +309,10 @@ class ParseRootDeviceTestCase(base.IronicLibTestCase):
         self.assertRaises(ValueError, utils.parse_root_device_hints,
                           {'hctl': 123})
 
+    def test_parse_root_device_hints_invalid_by_path(self):
+        self.assertRaises(ValueError, utils.parse_root_device_hints,
+                          {'by_path': 123})
+
     def test_parse_root_device_hints_non_existent_hint(self):
         self.assertRaises(ValueError, utils.parse_root_device_hints,
                           {'non-existent': 'foo'})
diff --git a/ironic_lib/utils.py b/ironic_lib/utils.py
index 55dc88ce..05349ce7 100644
--- a/ironic_lib/utils.py
+++ b/ironic_lib/utils.py
@@ -52,7 +52,7 @@ LOG = logging.getLogger(__name__)
 VALID_ROOT_DEVICE_HINTS = {
     'size': int, 'model': str, 'wwn': str, 'serial': str, 'vendor': str,
     'wwn_with_extension': str, 'wwn_vendor_extension': str, 'name': str,
-    'rotational': bool, 'hctl': str,
+    'rotational': bool, 'hctl': str, 'by_path': str,
 }
 
 
@@ -348,6 +348,8 @@ def match_root_device_hints(devices, root_device_hints):
                      (not rotational).
         :hctl: (String): The SCSI address: Host, channel, target and lun.
                          For example: '1:0:0:0'.
+        :by_path: (String): The alternative device name,
+                  e.g. /dev/disk/by-path/pci-0000:00
 
     :param root_device_hints: A dictionary with the root device hints.
     :raises: ValueError, if some information is invalid.